Graphene-cellulose-polyethyleneimine aerogels (GA-MCC-PEI) were prepared using a simple, environmentally friendly method to remove anionic and cationic dyes in water. Graphene-cellulose hydrogels were prepared using a hydrothermal method and then immersed in a polyethyleneimine aqueous solution for 48 h to obtain graphene-cellulose-polyethyleneimine hydrogels, which were then freeze-dried. The light and porous composite aerogels had a good compression resistance, and the maximum allowable pressure of the graphene-cellulose-polyethyleneimine aerogel with a cellulose content of 43% was 21.76 kPa, which was 827 times its weight. Adsorption of the anionic dye amaranth and the cationic dye methylene blue by the graphene-cellulose-polyethyleneimine aerogel was satisfactorily modeled using the Langmuir isothermal equation, indicating monolayer adsorption. When the cellulose content was 39%, the equilibrium adsorption capacities of the composite aerogel for amaranth and methylene blue were 369.37 mg/g and 237.33 mg/g, respectively. This graphene-cellulose-polyethyleneimine aerogel can be used to remove dye pollutants in water to maintain ecological balance, thus broadening the application space of aerogel materials, that is, as adsorbents in different environments.

The multi-layered and multi-material structures of a violin’s surface varnish film make it more challenging to comprehensively understand the patterns of sound quality changes during the coating process. Using an alcohol varnish coating technique on one or both sides of the wood, along with a combination of micro-morphology, material characterization, and vibration signal processing, this study traced and analyzed the changes in the acoustic vibration properties of Norway spruce wood during the coating process. The results showed that the acoustic characteristics of the coated wood tended to change in an unfavorable direction throughout the coating process, and the specific dynamic elastic modulus (E_sp) of the final single- and double-sided coating varied by −1.77% and −6.07%, respectively. The loss angle tangent (tanδ) had the opposite trend, with rates of change of 20.76% and 30.42%. The sizing and priming treatments in the pretreatment stage had some positive effects on the acoustic properties of the wood specimens. Additionally, significant changes in acoustic vibration performance parameters began to be highlighted at the color paint stage (p < 0.05). These insights provide reference data for the improvement of violin acoustic performance and the simplification of the coating process.

The acoustic vibration performance of wood affects the quality of many musical instruments, and the variability of wood causes obvious differences between individual timber samples. To mitigate the variations among the individual timber samples intended for musical instruments, in this study, we combined finite element simulation with experimental testing to investigate the effect of the periodic annular groove structure on the comprehensive acoustic vibration characteristics of wood. The results revealed that there are discernible correlations between the structural parameters of the periodic annular groove and the key acoustic parameters of wood, including the resonant frequency, equivalent dynamic modulus of elasticity, equivalent specific dynamic modulus of elasticity, equivalent acoustic radiation quality constant, and equivalent acoustic impedance. These relationships can be used to fine-tune the overall acoustic vibration performance of wood and harmonize the acoustic vibration characteristics among different timber specimens. The effects of the periodic annular groove structure on the five acoustic vibration parameters obtained through finite element simulations exhibited minimal differences to the corresponding results from experimental tests. Furthermore, there was a remarkably strong correlation between the outcomes of the finite element simulations and the experimental test results, with the coefficient of determination exceeding 0.99.

The effect of structure on the vibration response was explored for four piano soundboards with different but commonly adopted structures. The vibration response was obtained using the free-vibration method, and the values of the dynamic modulus of elasticity and dynamic shear modulus obtained using the free-vibration frequency method (E_F and G_F) were compared with the dynamic modulus of elasticity obtained using the Euler beam method (E_E) and dynamic shear modulus obtained using the free-plate torsional vibration method (G_T), respectively. It was found that the soundboards with different structures had different vibration modes and that excitation at different locations highlighted different vibration modes. For all the soundboards analyzed, the E_E and G_T were higher than E_F and G_F by 2.2% and 24.3%, respectively. However, the trends of the results of these methods were the same. The four piano soundboards with different structures possessed varying dynamic moduli of elasticity and dynamic shear moduli. These rules are consistent with the grain directions of the soundboards and the anisotropy of the wood (the direction of the units of the soundboards). The results show that the vibration mode of the piano soundboard is complex. The dynamic elastic modulus of the soundboard can be calculated using the Euler beam method. The results provide a reference for studies on the vibration response, material selection, production technology, and testing of piano soundboards.

Resonance boards of Chinese traditional instruments such as the Guzheng and Guqin typically are arched, with the arch height influencing their resonance characteristics. This study focuses on Paulownia wood utilized for resonance boards. The bottom surfaces were thinned in 1 mm increments, with vibration signatures acquired at each reduction stage using a multi-channel FFT analyzer. Subsequently, time-domain characteristic parameters of the signals were extracted through MATLAB-based signal processing. Modal and harmonic response simulations of the structure were conducted using finite element software. The results indicated that variations in arch height affected the frequency spectrum response of the vibrations of Paulownia wood, altering the structural energy radiation levels. Lower arch heights (0–2 mm) had a greater impact on the fundamental frequency. The arch height was 1 mm and 2 mm, with R1,1 and R1,2 being −5.31% and −8.62%, respectively. Skewness and kurtosis were negatively correlated with arch height. When ΔH was 3.06, the radiation effect was optimal. The changes in arch height influenced the vibrational modes and energy distribution of Paulownia. Higher arch heights (3–6 mm) have less effect on the fundamental frequency and impose some constraints on the mode vibration pattern. Furthermore, the results of the frequency-domain and time-domain analyses were found to be largely consistent with the finite element simulation results. The results provide guidance for changing the arch height to modulate the acoustic vibration response of the resonance board, which is of significance for the personalized design of future musical instruments.

Varnish coatings affect the vibro-mechanical properties of wood by altering its material properties, but the underlying mechanisms remain to be further elucidated. This study combined microstructural and performance characterization with vibration signal analysis to investigate the influences of multi-layer essential oil varnish coatings on the dynamic response characteristics and acoustic vibration properties of Norway spruce wood. The results showed that, after coating, the varnish–wood composite system exhibited increased density (ρ) and damping (tanδ) but decreased stiffness (E), leading to lower resonance frequencies, faster vibration attenuation, and reduced relative acoustic signal energy (single-sided coating: −24.33%; double-sided coating: −53.39%). The sound intensity reflection coefficient increased while the transmission coefficient decreased. Mediation analysis based on the MEMORE (Mediation and Moderation for Repeated-Measures Designs) procedure indicated that the coating affected the acoustic vibration performance of wood by altering its material properties, with the full mediation effect of tanδ not being confounded by mathematical relationships. This study demonstrates that surface coating alters the acoustic properties of wood through mass, stiffness, and damping effects, providing a reference for the design of coatings and performance regulation of wood used in musical instruments.